SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '784c136c7316f9deaf1f07c78e479fdfb5bb0f9f249f2ac453e6f5da80b0d8f7' 
  AND token = 'B50CiAcHrjUzi4YZNUnALVZdBy73isqggmgZZWa6GpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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