SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2696815159e613d56504eff9ab5ad017a847713bb516741a90b97346f084b52a' 
  AND token = '8SZ0osjO2N2r+jX7FfwEKJN676fEWxe5pKt4Tp4S4Rw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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