SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69f98645b6cf84217c0ba003a0e406574a47f53e9da4d9f298711d2db62b79df' 
  AND token = 'Q++LO/vdMLRtYra4e0mDJTqmULEkKa7hkpwPHfM7CXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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