SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e768469efccae364ccc9c1bf54fcd9b42e9645a840e442f6eab4669f299d163a' 
  AND token = 'nnu5dVixHnRkI+9oGwv5jMIIcTZ/txG3YtPvkGRqZ3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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