SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a28d0270f1df35a9b38dc81cd9fc70e298c12b3ebcfbc2265f9458f8ab89264' 
  AND token = 'dpjn/8KEeBN2u5gXs1KCJnayvTnVXbR8RYy2pQ+KtUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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