SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '154dcb9a223da6548886c8c0c154ac21708e2a85666ce616dc2a09fc0c66961a' 
  AND token = '4qbgHI33LcIYTuEsZl5wlxbVnScSkka5QbAaznS7o5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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