SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd9c67c8b22591c664ce476ee0b3d69c0df9a1d0a540db378b9caf14af1d0152' 
  AND token = 'uokGRMn5jLwfeONqa4ZBJ9K3WGQBz2bG4hyro5RXVg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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