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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ae1a92e98f4705d3d4586e3e55a96d4d9c2359d964ee3d17d1912cc8e50fee4' 
  AND token = 'SnmA5w+Rnbsr0FdkroM+VoYV1AQT9EtA3qTNZ4/HjWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}