SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f36b4f58d497e3cee474119580ecd772292b30bcd9995ecd9542bf34f9511445' 
  AND token = 'k3BPSZIPBDlk7H/RAgf6qwC2JkzPyCZtq/abhW/BXL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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