SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70bbe7b5a218173009bfc2d65ffca2a423c1c6edc1199dd161ae922e0147886f' 
  AND token = '/VMkJud+xaILYlZvR1hkAdrjlmM+DwvusVfYh4w9eLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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