SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '894a0af213f19dd0c02890d2fd7424980dce1d63a79ef8f7a904a9462f4cd1d1' 
  AND token = 'x2qJVWo0bcPiSVI2yln83nTFzip5sIEjh6WT+IeiX5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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