SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80aed5a60223940109ccde23de11dc5e68a21461cec02c09cccd24561b091a76' 
  AND token = 'FIJsuwiOANikuFAxBuLNOkPube2RaOxUSLZh3dzn+O8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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