SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfb050fa43ac46bf2b3de8f82a4dc4028f15904b31e77901959e7096a163ae37' 
  AND token = 'yoBnfw3ehNtLww6b9TYqXuqDgfK8wJ/hKM/TIXqSCrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}