SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c46684820ee9e1f0fe80afaf5fc05e0176ca095937d188043cb0a72aa062cf92' 
  AND token = 'bU1mgXfYiExzIWEq2opvXAhx4cV0LKNcbHgXKBQOkVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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