SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e0e09b89f5756179292e047daa8d844164bc2f112dda90745436474442cf802' 
  AND token = 'RNsiZYm1YxHb8CcUBN3bwRsi0+EzugRstizsJghOA1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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