SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8af03a2f1125af416cca0855e45bced639cdcacf11075c10cc3b9e8919ee1ed7' 
  AND token = 'e9Fu72zASroLGrfkxkSZFcpfIa9IFKMDIJ26DWEBKlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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