SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31595d520a91ba3364bf71c70a60d7da80772cefb843878184e4c84cc3278adf' 
  AND token = 'pxtNQdp/4arXq/OWv+M+p58/5bCafXSJKHTyWhLMpBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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