SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fd5d016c35bf740a9c9acaf2ccb01e0f61288887956141ed051302fbc997fb5c' 
  AND token = 'BHqNmMCczwNGUujlM0hQzmuk6sqm+1WwG4yTIPThV/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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