SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f99d26c78813802e8ec7ea135ba43a5b6e52f1bab03d292c09229be0a4901447' 
  AND token = 'Jn+SQns8N9lqZPgX9+fhlqo/vAGHvjnPBrgOVmZdH3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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