SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23540809a8111771436bcb7b3b73ab7c0ec07fe952d7cd9b54e9eb8dbc1977af' 
  AND token = 'QCX0QA1TVs6v0u/AoYbSlhfj6kGJQnL+rg5wwaGnNm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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