SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8cf6220523f65780701f8bbffed280e7846f079c03764b597ba1c0870ec828c' 
  AND token = '+IFOdI1TJvvQ/lqkzASOvFe3CYdKDvYvAalfTKVp/iM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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