SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ff97f5b7ff56c249616bb03ec5111f3cd157d271ce2af4fb90e55d363ad8904' 
  AND token = 'OYp570Q9RRl7PRXiSmZnZGl+R63iouWnlPWgM/eSXT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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