SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd72a5b26a07b5aaf0ebd1d1888a2d16d487fffc319fbf5a1f063c30d6c3462c5' 
  AND token = '6Jh08zqYTvv1uSK6YCJ9rL4FQmtqjQofuY9dqKrhb/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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