SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '490571fad986ac4c07645a728adac553222e72fa1b7f1be65ba9b8442cbb078a' 
  AND token = '5AfIE+E4zmYZ/JG+HB8Dz2sj+LUzOg5IqZikiL6pR/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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