SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6aeb0150696c244dcd529c9e4b5237083cb540a309d174d1806732292a3f99b' 
  AND token = 'sY2ZhbMpfz4HSJaYfM39T3VZCRZQlY4Xp40FeGkP1G0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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