SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '410b1fa545864de1bc67a16665cfd6ec945527519149a689ae89a0580efa17e8' 
  AND token = '+e+QFWPspFZWKQ6oYxy8kJCjRROU0e9494o8faMQ8Ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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