SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9d51e70f7ed4a2e239c394210eaeb28fa0590c66afffe7b14fcc0a04a195426' 
  AND token = 'stKD1ihmnEDOBpXqoNO7ze7rUcyEXjpsfOZtZ6vz30M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}