SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b76b50ba3f62908b6ec6e2a4a9938153f56b3c4f14d438e1f3a66f25a9b584f1' 
  AND token = 'LM2lGzvMK9zN0OdcC0qDIBYVGaL7aqQ830hVUC+5PCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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