SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9a39602c37e2746198ca47610bee22fa7934acd60f54d988caec8e3837af34e3' 
  AND token = '8Hew5HEqmpBQYh48o6zcWoEdCLr+vgKviZ+p/GzlLfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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