SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0ebf83a799bbaabaae0a59d113d53ce014dc46ac8978e08c56fb9b8dee71521' 
  AND token = 'BFyj3/4YPDyTPlyiJmmzm8QmsWIc5aECEEb4dW4GVvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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