SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40b52ea76e9ced811c18cf7be3a316877eea976565a7256b0f9d078f99b562d8' 
  AND token = 'CBqEj/SEtN8aVFHJTinx8rkP4WJq/PrgzBpwfSG4dzY=' 
  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"
    }
  }
}