SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '738383a8462858ab26a314da0dd5c30c54f959b06c1861d24dfc78e058f54b55' 
  AND token = 'zlKnoUH7gNc9qN2+oCzVabYRB2T33vPz/Gtd6MqLBcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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