SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e2f0fb1926c78cc8f877a4d7cb500d45da4644fe6843c232247f5756a101952' 
  AND token = 'eFxz/9HTB/ZKXr54HPB4RlTZmWxxYdXmCC6WYuwyLnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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