SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c2972da06e0406edb2f77f5c2ef96b0111efe266a2e5d58738d163663a275a03' 
  AND token = 'yUG38vSLmAnSx1wZrq0YOxS1Cl1D/BFC7C2nR6Ry+7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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