SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29f8aa93955f932db247cf97a70886fed8cf299faf2a6b99d052b1aa6bbce1ba' 
  AND token = 'WHEwytSUZotGrBJwIKux8PuQjgqC88Hb7F6VDZqKZc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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