SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b5dd090436efb97dddec5b5c8643ec586c8937f4c2379e45e728564230cb631' 
  AND token = '8zuT6JHwqyrN+5EI6qOWHCujJG/Zf4dMPgKsJFD9qBs=' 
  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"
    }
  }
}