SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98a3eb4c58b56e275bfdc085c5eaea759bd1eb1400d2c66682a149ae81db00ff' 
  AND token = 'uo4ccMJtPxSswvmbUuB2LeLT44O85NVUSzQZQ+vOggg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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