SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46d9c85c0620c9771b8ffa6d8d1c38adea2545bc15a9d8cabd9c10879753d438' 
  AND token = 'WIuLpnIDGSBxf06jRVkbYhguFbsiW2OddPGb+sFGJvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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