SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2946af6a968fc4f066a59a6bf07d1a4e715bf7c3b49325cca05d582fe60b59f' 
  AND token = 'nIKPwgumXNUawTCCy7zgS8LUgY19rSl66+RTZj/4gw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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