SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c955578fae3872cd04c6d13b6268570e423a1a90dbc67fd6f44713170803462' 
  AND token = 'iuCINwIb4AKeHgJDtTth/mmylKK8uheIff5G93FzWVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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