SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7473bfd47df212e0c5e76d923cb9f4de9af25c8155d77ce30bbf8c0b1925ffa6' 
  AND token = '+6v1RPYRvNTtDAwc2MHBGnOCfsLwfjHs8g+4peuJnoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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