SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5838edf0794399d209265ee4435e1bae2b1f851531d67699afab75a97237b0eb' 
  AND token = 'SwCUssNUWF8xq2gLU33k706cIZyWmUp7Sy8K9qHnhHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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