SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0755c5cfff1e3c1bb15a76f9f9419e2a8fbadf2b9821ba554bdedf02d7544eec' 
  AND token = 'mC88pSrY8BhF+NA2BJ2G4ek64Dxd6D5bRZRGj83Hc1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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