SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c897c3ae4b6ae768a8b17367879e32c42794a3791bd52466df27380917bee02f' 
  AND token = '1/R1/axzMI6egdM+1TSYY2GBfOHqkvYkUC6dPD7w3ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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