SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4b63d9a3f45f7e948f7614870566bb4b4b0b06c87725ebde1dcc81894a8cfa6' 
  AND token = 'Ztz6SsvBUvmGNBr+WsPRuqTMnnksFrC3JdMJ5EfSZSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}