SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da3df6a36a1389f817131116c87ca1abdadc094453f711de281fa84bf28842bc' 
  AND token = 'q7qiLZgMLHfKOV6qT+deve9n6QaDW8xY7Vaatshng/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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