SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '92a0ffd79a42c4305e7112e2bf432437800847119f69ec3fdda84df2ad56facb' 
  AND token = 'j8DKYMliWAgsNgT1g6M5w64EG2+gD2GeLOAOLDEe/Sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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