SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70b97744ea6de91e6dd58056c9d0a55e60e258d7bca9c09dbbf8e29d21c0d071' 
  AND token = 'G8pGmwc2iliYGRnwo8LLEksJDCCfVJumIpPZgzbR5rM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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