SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a92071206dbabe0dcd96647c914398c486abac14f47d2a37162bfb255e5a5a08' 
  AND token = 'c1pGaBtgw0mvohuSdh1ziLtZCAPk+XNlznphmamfq5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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