SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1fa0a00a17cea195de18f6d061d97dccfcaad752192de08d91cf65dbf5dac24f' 
  AND token = 'DqZs7Szrrh7Vx8Ys6pgI06JURQ35HVY91TXi6MdgJp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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