SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a00d619091900c8f11f3e503d0e9395ccf15f7560c144c44cac50ebef13a5fb' 
  AND token = 'dujyxMFfzdSVxiCV/0JPRKvNrgmuHtrJTLMl0Mr1WiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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