SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b92bdb4efba9373987fe919d5018e9225cf7ba2734996924054b1187d175b064' 
  AND token = 'uCllC1tz+mdVltJuwW+7VnJsjxRfSUnNTj/SF+BPKJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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