SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bdb7f16f290e8da9680ee16150db5213e4cae68986cc803e18096c6426cc4dee' 
  AND token = '7aApeiTBn+fDfLY6r4Gu3vAvn9Zg4QCZ3t+zBWoMhpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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