SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4088dd5d69054a7816557450b0093d60d8b905aa949c52e11dba103eaaa9857c' 
  AND token = '3FBxc8OMKUfVuOAzGbdki4VSrXbPtZFYXqr3DBeGWQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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