SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '973af6c5f896708a620e0ffae8ed06435dbf4dc681abc5859491cdb1e972436c' 
  AND token = 'bPBw1G91wysTqgOxqDyD1xVpiZOma7g9FlRcDOTaP7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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