SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8741a0f1a8c57f1f83d61de21465b2f0d040c24ed9ee055231a7eb6a33a96e66' 
  AND token = 'p3+XVOJvU6AbpY1cgS7eRKsG1DpNk5y2Lgs/ww6whZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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