SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91f00f8aeac77d07add79f4d0720385362910b0626fc08e32cb44e6dedb489b2' 
  AND token = 'geOUAwhQ/BhBvgfnkzyz3EjAnJAdGWKeFuRjsRyWl+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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