SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5063eb4ee52d426ecace2a854273702765d6b34910974ee02b13cf232dc98b4e' 
  AND token = 'TuVdnD1ZYUSZ/+PZ2xiAfMJAJFnJR6UlPm/kE8vg9t8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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