SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '126137ea965e392b1cedf0dfff1bf76ff7ecac3e514be889707de6180db2d9ea' 
  AND token = 'rLHlv+HHZp3bq7jg6QIntsLLds3bdSZPs9DKmDwOAco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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