SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9115aa397da0fdf4fe1629e5d42773f577bd8c69d96bd42d3a436072c9600550' 
  AND token = 'y8XGrXh1uPQBKkquaAcUMvf2jimSdqKKs5pil4GGnbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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