SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'be43d3c0a87d63cc9141c5d39004f98ceacfb231ab5629ae5629fd6ccb587ca2' 
  AND token = 'BPddc1WwC45ZKDZEKR/oDN3T+9XpP+SQBOkEnJ9ibIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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