SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3018c49ba24b1aa18d4cf7045472471079235f94b08af073d8ddbee75ee9f53' 
  AND token = 'Hni/BBnfG+bPHfugINfWawYFwlW1dPOhivxGN/BDdQI=' 
  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"
    }
  }
}