SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4ebd3e76bcf01bdfecc4dee523560eae8584b0d987113b4d529448cec99e72c' 
  AND token = 'y1V0sbE5reKUMnx24ZMlzzDrfACPLIdpCQpSaYGVB4k=' 
  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"
    }
  }
}