SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab1cba5210debe8be3037883f26c1c5606c10fa438dac60111b9e6699b7ab6c7' 
  AND token = 'wjVsEPtTlTDpUFKcPJ4DvsTrnpBytACiycEja+uz0Is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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