SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff78680d58fba84f7bdc2e13b3ded89939c21e745b9235b556134dcaa59b0896' 
  AND token = 'e0kT9bu7JFNkiqmZPNmNOf6cQL2QRb14q48vfmjAtm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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