SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f83ad1ba2028c75f4b61205110a0e339ed47aaf1c529bd7c25ecdfec07684e9' 
  AND token = '4qEHqxX5n3VJjBIkQxmdlE/Nfl7/Qzr/eA5tdIxrEHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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