SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59d1fddf87634be83ef974d264f6c8056cc403f8dbbabb9a1d1ede55a8be7ca6' 
  AND token = 'e7wWRglYvg7VeB8rPWKSVNmcJrxm/qzX2v4qRWi7rZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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