SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca7a409c3636c7f2b4d1f0d727e891693816fbb400003c42269cfeb4a9f41e91' 
  AND token = 'bRRqibbbx+/mwiF/xzkRVJFvXKgsfs4JQsg6oeRWdyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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