SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1782779146c7f729d383916955f662c9b4567682dbb0d8b48ff999b33ac0f428' 
  AND token = 'xJl+unfrSmhGQ+c2CWufcd+CB4KZJLxWeBKe76GS1F0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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