SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b67c8683d5538605727c39f27a886f1f5c9fb1573bac795fa3af6bda452b437' 
  AND token = 'q4jowhxSzjpoaB67FZp9zXQCVRtD4WeHpAFBZEy32Ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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