SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57592eed065e2a2775a1979a46a3add2d0815be25d440bd96dfb821e9a6a44a1' 
  AND token = 'Y5FsEh34AOY42aXoXWiPHNRtJPhavxUxHED9aUaQ2TM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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