SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf8fde8eb66663a510b1b631aef2dd2a8a94614dce966247df48dc0d12c16d8e' 
  AND token = 'UV91CRaakbOiutvur5dwDtoHMCRlx/bIDMqX2GJ5vBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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