SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90f66a166459747ad6e13ca7f6510980cd5ee63e7b0ec302f2fde92ec74de15d' 
  AND token = '7R7Mto+1MQ1XpI7qQQqexShAvR2DOA9zAujgWkE088M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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