SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42560f8abf333a581f73bfc4b5f078df936b0e2fa80009fb6c0e2d54347c3319' 
  AND token = '1wRGFrxA885VfQKg1H+34DxykIBDEpUnBr5HC2DK5XA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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