SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f3021872e67cfa594d907a213203b0db0b712737771f26bf8c88584e980402b' 
  AND token = 'MEQ66TyKXqV/e9DKfGq2xbeqWneczhzPjeG8dNndquU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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