SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d1d51316a52589a9419f2562efc74cdf0d02e3239e7b9a71c3aa85427331f6c' 
  AND token = '+Bd4yFvNqCvHGXtkHXJgB9h/7w+egrCF6YaNEoqE2Eg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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