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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec083e9711c3a8c6de9097ffd4d0e91b5b0e21cebb8e840b56e7dce0eda989ed' 
  AND token = '6lpfrNVJcLBVaqv9JP/VXL0pcTB8qG+jSTkBb2ecs/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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