SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '10971eb58e5b407a28d2e4f570455bf145c4625c07f66c4077eda696762e30c3' 
  AND token = 'D7EqCzCvJez1vcHwYuN7JHhHgmDhqwfow99rs6ob4fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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