SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '52a2a65cc92d31cf461b0134e2c6d4d762fc6403396cdee1fea83eb64f1966c9' 
  AND token = 'gLt77g4MSCyGvcMIA1O3vlMOgy+iPKFn0Z+KvbPWSas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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