SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '74bd3e5411a9a972c20656a28c3745c57db37bf58a663b5b080028ab92d928c7' 
  AND token = 'ds8oSYLteuVKZCpInU6HmJFmr+8pHCHvJrC8DdHVvoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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