SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26f1ede5189dbef996293088e88a6caf207187da12a392b24a8be82250cb9fd4' 
  AND token = 'SZ54gmdcZQZ56ZIVwfzUx4NtfI7pNUcbjFsLZGFQBpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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