SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a20a9cd835b66c81b18e1a34f8d462e85439bd537d7ecbe43f92c80800e572a' 
  AND token = 'EU2tCn4sLMfPCuyXn1TU31+f0VuYZ/aSxZNRgOzHSfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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