SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a9b66b76d791cee2fbf4e12611e29f75eea285e5f808e606a29fb7952a34628' 
  AND token = 'whgfxHFwD9BRArq8j6I5Mx+minZJXpqvj/PgxcVNOoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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