SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef37c1ecfce1d0754f6da29d457035af015ed3c6c3529136b8de28b05adae3e5' 
  AND token = 'rwdMIjPSTktuChFMaqVNoRbU7QfsJdkPyTmKBNYhR48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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