SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85998a77731fef5ab5d1d654dbd5f04238a673e8cc7f5b72e98be096b229ab4b' 
  AND token = 'UwcecPKkFbp+rDkcbjRLc62IWVAlRt4Ut5E0fuNDsw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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