SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a0f31780bf34da10365936adf31397323fc0f310593ca4a48f23d2b26387fc6' 
  AND token = 'C6gv12HqIAKIPWwm2so7uwDir2PrxH2HrDwZygsGC/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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