SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '516e26a05280b078beef512cc90cbbd951a15793f827324c66e333ec7083a1ba' 
  AND token = 'Epbq9Edah/Jk/JdqVyYoqN4Gi6whwX7kZlJ8ocOjXpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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