SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '547f65f9a674d44a1b5e9a7ed963ec77b211883dbf7a86a52907bedfda92ca5c' 
  AND token = 'qESd0fq4gU3AcL94BcFkG4gFsUPu+jgWHT5Phn7IhLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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