Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21ac0c8693ad4ceff552d4859245e11bdf17851a281f3e7f29c4cc2f90b558dc' 
  AND token = 'mxADbKUCP7Ec33mh4rBD7+51WiLJuLIQJDCdgqL0yQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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