SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '501fa98c09875db7fec60e6321fb051280d474e797a0cf6e644adb4633d9d15c' 
  AND token = 'hAoDLu4Ch4Jv+iv44Og+QukceXBK1hdL4UaYJXWK2B8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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