SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e72643b78537b9837b29d219aba0d1e4b71c1b09d181bd906e1722208a483302' 
  AND token = 'gNUc3ir38VjSjFIBzDCFZ/tXM3P+7bEek0jiGNdCF2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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