SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bce8066e31acc67aedb4a1a0e061348edaef397001d85e82b60bafc742e73276' 
  AND token = 'wZLK/mJUFK1p20wQkE7hF1j3brZ/VuaWXnoXw1WhFqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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