SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2ac7ba273261a92a29149f16dc8b8134abdde536a949ad17c7bee540a5c57e8' 
  AND token = 'AgSDQz5cxzrOSccWltupWOhzbImMG4+K/Bkkjqm/ce4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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