SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '159e2f573f29c2089da71ca2156e9c0d74186cb297b154ee1a9a63139d39586c' 
  AND token = 'FEkMbg9F5wL3MwiE+QF9vlRraJS4/LYnKq68TA7u0BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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