SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '057e3d42b483c27924acf79bce1f39e1bba27a65d732ae9050719847f90da79d' 
  AND token = 'UIwqlkz+qsLZV9jMPopgMSBYKFW+S3B4sut0W2IjfS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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