SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f2ed9c9df429a42a5f722ab0c83882d44c65ac1575b196dc33f5a8c0f7073c2' 
  AND token = 'xk7Ig2SGDe0+iPu0euQINvjwUFR/h+t3LH2mZU+nAhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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