SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3da9397d5ae1682423fc19edba80d8dc71ff7086441e3f5c97067e0a92b17582' 
  AND token = '+hQgJhB6ZkKLVHS3KiA3WY9hDKXN88C/H/jnlY4bCfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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