SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6c8df23f5ffdf97af6975494f65e0658188cca1b9715db1e9ec757273db0da2' 
  AND token = 'zlp/uevqu+Lh9uC8XAEbHiQod48JeGuzESSrIqCG8js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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