SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39fdccf8d69dc11840fc21b455ee7ba9b641fb7929e0cdc00958fd869a198ee3' 
  AND token = 'JMGUkveq0/PoA0zDebEZNwmkCUiUO/UfKyqk7v2auIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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