SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6c637c1213b464de130b00ee5df1b6f9350a864bd6ad86a0219b5e33e1250f2' 
  AND token = '597xMjy0LkLleeXVsv4D8sRLUq4AMogJH6H+OQZE+q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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