SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36a9b18de73de2436afe0962036d31d4baad9213e92c4b6bdb497beaa370a423' 
  AND token = 'kDnu5CbbpFeyvbIw+xGiPC46nwwM2ztSLeo0do6RrDQ=' 
  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"
    }
  }
}