SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da7cadef561804511c4ff35ed839c9666cc4e602ab5e227b0446f96855b824b0' 
  AND token = 'IeGWQwJH2EZYCCetjMiCrXl5KK+t3mVt30rgeGBKqBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}