SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29fd08fbe9f75d6ef33c22e2e4f7ae45717f1cb5fce6529d020b6ce1538b2c65' 
  AND token = 'XKFHeYxTvVUaFANnRMG7uuBZKxwsjlKd6qc4AhfP0uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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