SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9ea5b15b34d90b8cb2b07065000c2698feb583f0ce07a1c8279c761014582f3' 
  AND token = 'xc98LwBA8HgutejQ6hBAq2GGAQMISkQkTEgpnu89Z7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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