SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6db5ec6200308d239fa63987996ff8a2877ce3cd5b10f61548059701ec12fc80' 
  AND token = 'E/el+1JR5DFJKHEaa9xgu3f2MtCB0P1xqUI1a95VMqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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