SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80c281742fc9b54d92c80a046f907c44eaefd776545be5240fdb954f87791f68' 
  AND token = 'lHcCi3BiafsjUiNwLQqWm7pMJ8w8sB8Uj1Nw8QUdX24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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