SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f66ea2a4a7683725d91a9f92fa516f7f20aea69659f5870802daad888e03327d' 
  AND token = 'uxRl2Jz9gL+S/e4XvVtJBuMei4BxPxemeIetvM6R8Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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