SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e4488d1d70d0bff7b93b165f04b541edda5ba6bc86f80c966d38bb441806954' 
  AND token = '/4GYCNew6HXOcCuSj+M7hbivo52y9oJlYmjvUdDhUZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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